Spindle motor

ABSTRACT

A spindle motor is provided, the motor comprising: a base plate, a PCB on the base plate, a bearing assembly arranged on the base plate, a stator coupled to a periphery of the bearing assembly, a rotor rotationally coupled to the bearing assembly, the rotor including a yoke and a magnet, and a rotation shaft rotationally coupled to the bearing assembly. The base plate includes a planar portion and a protruding portion arranged along with a periphery of the yoke, the protruding portion being apart from the yoke. The base plate is partially covered with the PCB in a region where the stator is arranged. And, a height from the planar portion to an upper surface of the protruding portion is smaller than a height from the planar portion to a lower surface of the periphery of the yoke.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/444,711, filed Jun. 18, 2019; which is a continuation of U.S. patentapplication Ser. No. 15/880,130, filed Jan. 25, 2018, now U.S. Pat. No.10,373,644, issued Aug. 6, 2019; which is a continuation of U.S. patentapplication Ser. No. 14/598,899, filed Jan. 16, 2015, now U.S. Pat. No.9,911,455, issued Mar. 6, 2018; which is a continuation of U.S. patentapplication Ser. No. 14/104,856, filed Dec. 12, 2013, now U.S. Pat. No.8,963,386, issued Feb. 24, 2015; which is a continuation of U.S. patentapplication Ser. No. 14/054,333, filed Oct. 15, 2013, now U.S. Pat. No.8,963,385, issued Feb. 24, 2015; which is a continuation of U.S. patentapplication Ser. No. 13/299,661, filed Nov. 18, 2011, now U.S. Pat. No.8,587,166, issued Nov. 19, 2013; which claims the benefit under 35U.S.C. § 119 of Korean Application No. 10-2010-0115160, filed Nov. 18,2010, which are hereby incorporated by reference in their entirety.

BACKGROUND

The present disclosure generally relates to a spindle motor.

A spindle motor performs a function of rotating a disk to enable anoptical pickup which linearly reciprocates in an optical disk drive ODDand a hard disk to read a large amount of data recorded on the disk. TheODDs have been recently developed to stably rotate an optical disk at ahigh speed.

The ODD includes a spindle motor for rotating an optical disk at a highspeed, an optical pickup module for reading out data from a diskrotating at a high speed or recording the data on the disk, and astepping motor for driving the optical pickup module.

The spindle motor rotating the optical disk at a high speed includes abearing rotationally supporting a rotation shaft, a bearing housingaccommodating the bearing, a stator secured at a periphery of thebearing housing, a rotor rotationally accommodated on the bearing, abase plate fixing the bearing housing and a circuit substrate arrangedat an upper surface of the base plate.

A gap is formed between an upper surface of the base plate and thestator according to a conventional spindle motor to disadvantageouslyintroduce foreign objects. In order to reduce the gap formed between thestator and the upper surface of the base plate, the circuit substratearranged on the upper surface of the base plate is unnecessarilyextended to a bottom surface of the stator. If the circuit substrate isextended to between the stator and the base plate, inflow of foreignobjects into the base plate and the stator may be reduced to a certaindegree. However, a problem occurs in which an area of the high-pricedcircuit substrate disadvantageously increases to increase amanufacturing cost of the spindle motor.

BRIEF SUMMARY

Exemplary embodiments of the present disclosure provide a spindle motorconfigured to reduce a manufacturing cost by dispensing with unnecessaryextension of a circuit substrate into between a stator and a base plateand by inhibiting foreign objects from entering the stator and the baseplate.

In one general aspect of the present disclosure, there is provided aspindle motor, comprising: a base plate; a PCB on the base plate; abearing assembly arranged on the base plate; a stator coupled to aperiphery of the bearing assembly; a rotor rotationally coupled to thebearing assembly, the rotor including a yoke and a magnet; and arotation shaft rotationally coupled to the bearing assembly, wherein thebase plate includes a planar portion and a protruding portion arrangedalong with a periphery of the yoke, the protruding portion being apartfrom the yoke, wherein the base plate may be partially covered with thePCB in a region where the stator is arranged, and wherein a height fromthe planar portion to an upper surface of the protruding portion may besmaller than a height from the planar portion to a lower surface of theperiphery of the yoke.

In some exemplary of the present invention, the PCB may include anexposure unit exposing a part of the base plate opposite to the stator,and the protruding portion inhibits foreign objects from entering to theexposure unit.

In some exemplary of the present invention, the base plate may include afirst through hole to be coupled to the bearing assembly, and the PCBincludes a second through hole formed at a position corresponding tothat of the first through hole and partially opened toward theprotruding portion.

In some exemplary of the present invention, the protruding portion mayinclude a shape of a curved line when viewed in a top plane.

In some exemplary of the present invention, the protruding portion mayhave the same curvature as that of a core of the stator.

In some exemplary of the present invention, the height from the planarportion to the upper surface of the protruding portion may be the sameas thickness of the PCB.

In some exemplary of the present invention, the protruding portion mayprotrude with a right angle relative to the planar portion.

In some exemplary of the present invention, the height from the planarportion to the upper surface of the protruding portion may be higherthan the thickness of the PCB.

In some exemplary of the present invention, the protruding portion mayprotrude with an obtuse angle relative to the planar portion.

In some exemplary of the present invention, the protruding portion mayprotrude with an acute angle relative to the planar portion.

In some exemplary of the present invention, the protruding portion maybe integrally formed with the planar portion.

In some exemplary of the present invention, the protruding portion maybe integrally formed with the planar portion by bending a part of thebase plate.

In some exemplary of the present invention, the protruding portion mayinclude a semi-circular shape when viewed in a top plane.

In some exemplary of the present invention, the bearing assembly mayinclude a bearing housing and a bearing inserted into the bearinghousing, the stator may include a core including radially formed corepieces and a coil wound on the core pieces, and the rotor may includethe magnet opposite to the core pieces and the yoke fixing the magnetand coupled to the rotation shaft inserted into the bearing.

In some exemplary of the present invention, the PCB may be formed with athrough hole through which the bearing assembly passes, and a diameterof the through hole may be larger than that of the bearing assembly, andthe through hole may be partially opened.

In another general aspect of the present disclosure, there is provided aspindle motor, comprising: a base plate; a PCB on the base plate; abearing assembly arranged on the base plate; a stator coupled to aperiphery of the bearing assembly; a rotor rotationally coupled to thebearing assembly, the rotor including a yoke and a magnet; and arotation shaft rotationally coupled to the bearing assembly, wherein theyoke may include an upper plate and a lateral plate, wherein the baseplate may include a planar portion and a protruding portion arrangedalong with the lateral plate of the yoke, and wherein the protrudingportion may be configured to have a gap between the protruding portionand a lower surface of the lateral plate of the yoke.

In some exemplary of the present invention, the PCB may be partiallyarranged on the base plate in a region where the rotor is arranged.

In some exemplary of the present invention, the base plate may include afirst through hole to be coupled to the bearing assembly, and the PCBmay include a second through hole formed at a position corresponding tothat of the first through hole and partially opened toward theprotruding portion.

In some exemplary of the present invention, the protruding portion mayinclude a shape of a curved line when viewed in a top plane.

In some exemplary of the present invention, the protruding portion mayhave the same curvature as that of a core of the stator.

In some exemplary of the present invention, a height from the planarportion to an upper surface of the protruding portion may be the same asthickness of the PCB.

In some exemplary of the present invention, a height from the planarportion to an upper surface of the protruding portion may be higher thanthe thickness of the PCB.

In some exemplary of the present invention, the protruding portion mayprotrude with an obtuse angle relative to the planar portion.

In some exemplary of the present invention, the protruding portion mayprotrude with an acute angle relative to the planar portion.

In some exemplary of the present invention, the protruding portion maybe integrally formed with the planar portion.

In some exemplary of the present invention, the protruding portion maybe integrally formed with the planar portion by bending a part of thebase plate.

In some exemplary of the present invention, the protruding portion mayinclude a semi-circular shape when viewed in a top plane.

In some exemplary of the present invention, the bearing assembly mayinclude a bearing housing and a bearing inserted into the bearinghousing, the stator may include a core including radially formed corepieces and a coil wound on the core pieces, and the rotor may includethe magnet opposite to the core pieces and the yoke fixing the magnetand coupled to the rotation shaft inserted into the bearing.

In some exemplary of the present invention, the PCB may be formed with athrough hole through which the bearing assembly passes, and a diameterof the through hole is larger than that of the bearing assembly, and thethrough hole may be partially opened.

The spindle motor according to the exemplary embodiments of the presentdisclosure has an advantageous effect in that an exposure unit is formedat a part of a PCB interposed between a base plate and a core of astator to reduce a manufacturing cost of the PCB, and foreign objectsintroduced through the exposure unit is inhibited by a foreign objectinflow prevention fence formed at the base plate to avoid the spindlemotor from being polluted by the foreign objects.

Additional advantages, objects, and features of the disclosure will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of thedisclosure. The objectives and other advantages of the disclosure may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Accompanying drawings are included to provide a further understanding ofarrangements and embodiments of the present disclosure and areincorporated in and constitute a part of this application. In thefollowing drawings, like reference numerals refer to like elements andwherein:

FIG. 1 is a perspective view of a spindle motor according to anexemplary embodiment of the present disclosure;

FIG. 2 is a cross-sectional view taken along line 1-1′ of FIG. 1;

FIG. 3 is a plane view illustrating a spindle motor of FIG. 1 removed ofa rotation shaft and a rotor;

FIG. 4 is a partially enlarged perspective view illustrating a spindlemotor of FIG. 3 removed of a stator; and

FIG. 5 is a lateral view of FIG. 1.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure aredescribed in detail with reference to the accompanying drawings. In thedrawings, sizes or shapes of constituent elements may be exaggerated forclarity and convenience.

Particular terms may be defined to describe the disclosure in the bestmode as known by the inventors. Accordingly, the meaning of specificterms or words used in the specification and the claims should not belimited to the literal or commonly employed sense, but should beconstrued in accordance with the spirit and scope of the disclosure. Thedefinitions of these terms therefore may be determined based on thecontents throughout the specification. The meaning will be clear fromthe context of the description. Like numbers refer to like elementsthroughout, and explanations that duplicate one another will be omitted.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. Such an industry-accepted tolerance rangesfrom less than one percent to ten percent and corresponds to, but is notlimited to, component values, angles, et cetera.

Any reference in this specification to “one embodiment,” “anembodiment,” “exemplary embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the disclosure. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to affect such feature, structure, orcharacteristic in connection with others of the embodiments.

FIG. 1 is a perspective view of a spindle motor according to anexemplary embodiment of the present disclosure, FIG. 2 is across-sectional view taken along line 1-1′ of FIG. 1, FIG. 3 is a planeview illustrating a spindle motor of FIG. 1 removed of a rotation shaftand a rotor, FIG. 4 is a partially enlarged perspective viewillustrating a spindle motor of FIG. 3 removed of a stator, and FIG. 5is a lateral view of FIG. 1.

Referring to FIGS. 1 to 5, a spindle motor 800 includes a bearingassembly 100, a stator 200, a rotation shaft 300, a rotor 400, a baseplate 500 and a PCB Printed Circuit Board, 700. In addition, the spindlemotor 800 may further include a clamp 600.

The bearing assembly 100 includes a bearing housing 110 and a bearing120. The bearing housing 110 takes a shape of a hollow hole-formedcylinder, for example, and the bearing housing 110 is formed at an uppercorner with a staircase sill 115 for securing a core described later.The bearing housing 110 is protruded at a rear surface with a couplinglug 117 for being coupled with the base plate 500, described later.

The bearing housing 110 is arranged at a bottom surface with a supportplate 119 for supporting a bottom end of the rotation shaft 300,described later, and a portion contacting a bottom end of the rotationshaft 300 in the support plate 119 is formed with a thrust bearing 119a.

The bearing 120 takes a shape of a cylinder inserted into the bearinghousing 110, and is formed with a rotation shaft hole for being coupledwith the rotation shaft. In the exemplary embodiment of the presentdisclosure, the bearing 120 may include an oil sintered impregnationbearing.

The stator 200 includes a core 210 and a coil 220. The core 210 isformed by stacking a plurality of iron pieces each having an opening,and secured to the staircase sill 115 of the bearing housing 100. In theexemplary embodiment of the present disclosure, the core 210 includescore units 212, where the core units 212 are formed by being radiallyprotruded, and the core 210 including the core units 212 takes a shapeof a disk when viewed in a top plane.

In the exemplary embodiment of the present disclosure, a part of thecore 210 including the core units 212 may be arranged to protrude froman edge of the base plate 500. The coil 220 is wound on the core unit212 formed at the core 210.

The rotation shaft 300 is inserted into the rotation shaft hole of thebearing 120 at the bearing assembly 100, and a bottom end of therotation shaft 300 is brought into contact with the thrust bearing 119 asupported by the support plate 119.

The rotor 400 includes a yoke 410 and a magnet 420. In addition, therotor 400 may further include a suction magnet 430. The yoke 410 mayinclude a yoke upper plate 412 and a yoke lateral plate 414.

The yoke upper plate 412, when viewed from a top plane, takes a shape ofa disk, and is centrally formed with a cylindrically shaped yoke burringunit 413 towards an upper surface of the yoke upper plate 412. The yokeburring unit 413 is press-fitted into the rotation shaft 300.

The yoke lateral plate 414 is downwardly extended from the yoke upperplate 412 and a void is formed inside the yoke 410 by the yoke lateralplate 414 and the yoke upper plate 412.

The magnet 420 is formed along an inner lateral surface of the yokelateral plate 414, and a rotational force is generated on the yoke 410and the rotation shaft 300 by attractive force and repulsive forcegenerated a magnetic field generated by the coil 220 wound on the coreunit 212 of the core 210 and a magnetic field generated by the magnet420. The yoke upper plate 412 of the yoke 410 is arranged with a clamp600 for chucking an optical disk.

Meantime, a suction magnet 430 may be arranged at any one place of aninner lateral surface of the yoke upper plate 412 and an upper surfaceof the core 210 opposite to the inner lateral surface of the yoke upperplate 412.

In the exemplary embodiment of the present disclosure, the suctionmagnet 430 may be arranged at the inner lateral surface of the yokeupper plate 412, for example, and the suction magnet 430 arranged at theinner lateral surface pulls the core 210 using the magnetic force tostably rotate the rotor 400.

Referring to FIGS. 2, 3 and 4 again, the base plate 500 is formed byprocessing a metal plate. The base plate 500 is formed with a throughhole 502 corresponding to the hollow hole of the bearing housing 110 atthe bearing assembly 100, as shown in FIG. 2.

The base plate 500 is formed with a lug 510 formed in a shapecorresponding to the core 210 of the stator 200, and the lug 510 maytake a semi-disk semi-circular shape when viewed in a top plane. Thus,foreign objects can be initially inhibited by the lug 510 from enteringan interior of the spindle motor through a bottom surface of the core210.

The PCB 700 is arranged at an upper surface of the base plate 500, andis mounted with a variety of circuit elements, where the PCB 700 iselectrically connected to the coil 220 which is a constituent element ofthe stator 200. The PCB 700 is formed with a through hole 505 forinhibiting an interference with the bearing housing 110. Size of thethrough hole 505 formed at the PCB 700 is larger than that of a throughhole 502 formed at the base plate 505. The through hole 505 of the PCB700 is partially opened and the opened portion of the through hole 505may be formed with a curvature.

Referring to FIGS. 2 and 5, a bottom surface of the core 210 coupled tothe bearing housing 110 of the bearing assembly 100 coupled to the baseplate 500 is discrete from an upper surface of the base plate 500 at apredetermined gap, where various foreign objects such as dust, fineparticles, oily dust and the like can be introduced into the base plate500 and the bottom surface of the core 210, and the foreign objects canbe attached to the core 210, the coil 220, the bearing and the magnet420, and life of the spindle motor 800 can be greatly reduced by theforeign objects attached thereto.

In order to inhibit the foreign objects from introducing into the gapbetween the upper surface of the base plate 500 and the bottom surfaceof the core 210, a partial area of the PCB 700 may be extended to bearranged on the lug 510 of the base plate 500.

In a case the PCB 700 covers the semi-disk lug 510 of the base plate500, the gap between the upper surface of the base plate 500 and thebottom surface of the core 210 is reduced as much as thickness of thePCB 700 to decrease inflow of the foreign objects.

However, in a case the high-priced PCB 700 is unnecessarily extended tocover the lug 510 of the base plate 500, a manufacturing cost of thespindle motor 800 is inevitably increased.

In the exemplary embodiment of the present disclosure, the PCB 700 isformed with an exposure unit 710 that exposes the semi-disk lug 510 ofthe base plate 500 as illustrated in FIG. 5. The closed through hole 505formed at the PCB 700 is opened by the exposure unit 710.

In the exemplary embodiment of the present disclosure, the frequentlyused “exposure unit” is defined by a portion exposing the base plate 500that is formed by removing a part corresponding to a part opposite tothe core 210 in the PCB 700 arranged on the base plate 500.

A portion corresponding to the semi-disk lug 510 is formed the byexposure unit with a void space not formed with the PCB 700. In a casethe exposure unit 710 exposing a part of the semi-disk shaped lug 510 ofthe base plate opposite to the core 210 is formed on the PCB 700, anarea of the PCB 700 is reduced whereby a manufacturing cost of the PCB700 can be decreased but the foreign objects can be introduced in thespindle motor through the exposure unit 710.

In the exemplary embodiment of the present disclosure, in order toinhibit the foreign objects from entering through the exposure unit 710of the PCB 700 formed between the upper surface of the base plate 500and the bottom surface of the core of the stator 200, a foreign objectinflow prevention fence 520 is formed at the base plate 500.

The foreign object inflow prevention fence 520 is formed along an edgeof the semi-disk shaped lug 510 and takes a shape of curved fence. Adistal end of the curvature-shaped foreign object inflow preventionfence 520 is brought into contact with a distal end of the PCB 700formed by the exposure unit 710, and the other distal end correspondingto the distal end of the foreign object inflow prevention fence 520 isbrought into contact with the other distal end corresponding to thedistal end of the PCB 700 formed by the exposure unit 710.

In the exemplary embodiment of the present disclosure, a height of theforeign object inflow prevention fence 520 may be substantially same asthickness of the PCB, for example. Alternatively, it should be apparentthat the height of the foreign object inflow prevention fence 520 isgreater than the thickness of the PCB.

The foreign object inflow prevention fence 520 may be erected at a rightangle relative to the base plate 500. Alternatively, the foreign objectinflow prevention fence 520 may be erected at an obtuse angle or anacute angle relative to the base plate 500.

In the exemplary embodiment of the present disclosure, the foreignobject inflow prevention fence 520 may be formed by bending an edge ofthe semi-circular lug 510 of the base plate 500 to a direction facingthe core 210. In the exemplary embodiment of the present disclosure, theforeign object inflow prevention fence 520 formed by bending the edge ofthe semi-circular lug 510 of the base plate 500 is formed in the shapeof a curved plate.

Although a gap between the base plate 500 and the bottom surface of thecore 210 of the stator 200 may increase by the PCB 700 formed with theexposure unit 710 for reducing the manufacturing cost, the foreignobjects can be blocked by the foreign object inflow prevention fence 520formed at the base plate 500 through the formation of the foreign objectinflow prevention fence 520 formed at the base plate 500.

In the exemplary embodiment of the present disclosure, both distal endsof the foreign object inflow prevention fence 520 are brought intocontact with the PCB 700, whereby inflow of foreign objects areinhibited from entering a space formed between the distal end of theforeign object inflow prevention fence 520 and the PCB 700.

Although the exemplary embodiments of the present disclosure haveillustrated and explained a structure in which a part of the base plate500 is bent to form the foreign object inflow prevention fence 520, itshould be apparent that the foreign object inflow prevention fence isalternatively formed by a synthetic resin material hardened along anupper edge of the lug 510 of the base plate 500 in a strip shape andcoated on the base plate 500 using a dispenser. At this time, it shouldbe apparent that the synthetic resin material has elasticity free fromgenerating a static electricity, such that even if the synthetic resinmaterial is brought into contact with the rotating yoke 410, no noiseand damage can be generated.

Meanwhile, in order to inhibit foreign objects such as dust introducedthrough the foreign object inflow prevention fence 520 from attaching toessential parts of the spindle motor despite the formation of theforeign object inflow prevention fence 520, a foreign object attachmentmember may be arranged at a rear surface of the foreign object inflowprevention fence to which foreign objects introduced into the foreignobject inflow prevention fence are attached. The foreign objectattachment member may include an adhesive material having viscosity towhich foreign objects having passed the foreign object inflow preventionfence 520 are attached.

Meanwhile, the foreign object inflow prevention fence 520 inhibitinginflow of foreign objects may be manufactured with a synthetic resinmaterial, and the foreign object inflow prevention fence 520manufactured with the synthetic resin material may be attached to thebase plate by an adhesive.

As apparent from the foregoing, the spindle motor according to theexemplary embodiments of the present disclosure has an industrialapplicability in that an exposure unit is formed at a part of a PCBinterposed between a base plate and a core of a stator to reduce amanufacturing cost of the PCB, and foreign objects introduced throughthe exposure unit is inhibited by a foreign object inflow preventionfence formed at the base plate to avoid the spindle motor from beingpolluted by the foreign objects.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis invention. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A motor, comprising: a base plate; a bearing housing coupled with thebase plate; a bearing disposed in the bearing housing; a stator coupledwith the bearing housing and comprising a coil; a rotation shaft coupledwith the bearing; a rotor coupled with the rotation shaft and comprisinga yoke, and a magnet disposed on the yoke and facing the coil; and aprinted circuit board (PCB) disposed on an upper surface of the baseplate, wherein the base plate comprises a fence extending from at leasta portion of an edge of the upper surface of the base plate, wherein asuction magnet is disposed in the yoke.
 2. The motor of claim 1, whereinthe yoke comprises a yoke upper plate and a yoke lateral plate extendingfrom the yoke upper plate, and wherein the suction magnet is disposedbetween the yoke upper plate and the base plate.
 3. The motor of claim2, wherein the suction magnet is disposed at a position opposite to theyoke upper plate.
 4. The motor of claim 2, wherein the stator comprisesa core comprising a plurality of core pieces radially disposed withrespect to the bearing housing, wherein the coil is disposed on each ofthe plurality of core pieces, wherein the suction magnet is disposed onan upper surface of the core opposite to an inner surface of the yokeupper plate.
 5. The motor of claim 2, wherein the stator comprises acore comprising a plurality of core pieces radially disposed withrespect to the bearing housing, wherein the coil is disposed on each ofthe plurality of core pieces, wherein the suction magnet is disposed onan inner surface of the yoke upper plate, and wherein the suction magnetpulls the core by a magnetic force to stably rotate the rotor.
 6. Themotor of claim 2, wherein the magnet of the rotor is disposed on theyoke lateral plate.
 7. The motor of claim 1, wherein the fence iserected at an obtuse angle relative to the base plate.
 8. The motor ofclaim 1, wherein the upper surface of the base plate comprises a firstregion disposed between the bearing housing and at least a portion ofthe fence, and wherein the PCB is not disposed on the first region ofthe base plate.
 9. The motor of claim 1, wherein an imaginary lineconnecting the rotation shaft and the fence is not overlapped with thePCB in a shaft direction of the rotation shaft.
 10. The motor of claim1, wherein the PCB comprises a hole formed at a position correspondingto that of the bearing housing and an exposure unit exposing a portionof the upper surface of the base plate, wherein the hole of the PCB isopened by the exposure unit of the PCB, and wherein at least a portionof the exposure unit is formed corresponding to the fence.
 11. The motorof claim 10, wherein the PCB is formed with the hole for inhibiting aninterference with the bearing housing, and wherein a size of the hole ofthe PCB is greater than that of the bearing housing.
 12. The motor ofclaim 2, wherein the fence is overlapped with the yoke lateral plate ina shaft direction of the rotation shaft, and wherein the fence is notoverlapped with the yoke in a direction perpendicular to the shaftdirection.
 13. The motor of claim 1, wherein a distance between a lowerend of the rotor and an upper end of the fence is shorter than adistance between the lower end of the rotor and the upper surface of thebase plate.
 14. The motor of claim 1, wherein the fence isconcentrically disposed with the rotor and the stator.
 15. An opticaldisk drive comprising: the motor of claim 1 rotating a disk; and anoptical pickup module configured to read out data from the disk orrecord data on the disk.
 16. A motor, comprising: a base plate; abearing housing coupled with the base plate; a bearing disposed in thebearing housing; a stator coupled with the bearing housing andcomprising a coil; a rotation shaft coupled with the bearing; a rotorcoupled with the rotation shaft and comprising a magnet facing the coil;and a printed circuit board (PCB) disposed on an upper surface of thebase plate, wherein the base plate comprises a fence extending from atleast a portion of an edge of the upper surface of the base plate, andwherein the fence is erected at an obtuse angle relative to the baseplate.
 17. The motor of claim 16, wherein the yoke comprises a yokeupper plate and a yoke lateral plate extending from the yoke upperplate, wherein the magnet is disposed on the yoke lateral plate, andwherein a suction magnet is disposed at a position opposite to the yokeupper plate and spaced apart from the magnet.
 18. The motor of claim 16,wherein the PCB comprises a hole formed at a position corresponding tothat of the bearing housing and an exposure unit exposing a portion ofthe upper surface of the base plate, wherein the hole of the PCB isopened by the exposure unit of the PCB, and wherein at least a portionof the exposure unit is formed corresponding to the fence.
 19. The motorof claim 16, wherein the upper surface of the base plate comprises afirst region disposed between the bearing housing and at least a portionof the fence, and wherein the PCB is not disposed on the first region ofthe base plate.
 20. A motor, comprising: a base plate; a bearing housingcoupled with the base plate; a bearing disposed in the bearing housing;a stator coupled with the bearing housing and comprising a coil; arotation shaft coupled with the bearing; a rotor coupled with therotation shaft and comprising a magnet facing the coil; and a printedcircuit board (PCB) disposed on an upper surface of the base plate.